The number of food poisoning cases has increased with the worldwide increase in agrifood pollution over the past decade. Accordingly, there is increased demand for diagnostic methods for rapidly detecting contamination with food poisoning bacteria in the early stages of food processing/production, preceding the distribution of final food products, thereby preventing the onset of food poisoning and reducing the social cost of food poisoning. Conventionally, food poisoning bacteria are detected by culturing and biochemical assays, but it takes 3˜5 days to obtain final diagnostic data, which is too slow to prevent food poisoning incidents in advance of the distribution of food products.
To overcome the above problems, Korea Patent No. 1149418, issued to the Republic of Korea, discloses a method for quantitatively measuring bacterial amounts in which a fluorescent nanoparticle conjugate containing an antibody is added to bacterial mass and allowed to bind to specific bacteria, followed by quantitating the level of a specific bacteria from measurements of fluorescent intensity. To this end, a layer of the biomolecule avidin is formed on fluorescent nanoparticles (quantum dots, QD), and coupled with antibody-conjugated biotin. The resulting conjugate binds to the specific bacteria when the antibody reacts with a specific bacterial antigen.
In addition, Biomaterials 32(2011)1177˜1184, “A multicomponent recognition and separation system established via fluorescent, magnetic, dualencoded multifunctional bioprobes,” issued to Jun ha, et al., discloses a magnetic particle with a size of about 3 micrometers that is conjugated at a terminal carboxylic group with a fluorescent particle and an antibody. The conjugated magnetic particle is allowed to bind to specific bacteria, and is then separated by magnetism.
However, this method has difficulty in effectively separating bacteria-bound particles and non-bound particles, and suffers from the disadvantage that additional fluorescent particles are required for quantitative analysis.
There is therefore a need for a novel method by which bacteria-bound particles can be effectively separated from non-bound particles and can be readily quantitatively analyzed.